Effect of Low-intensity Aerobic Regular Activity on Heart Rate Variability in Type 1 Diabetes

Overview

A monocentric prospective randomized trial included 35 patients with Type 1 diabetes. Participants were randomized into two groups: Group A with the patients who engaged in low-intensity physical activity five days per week over a one-year observation period and Group B with the patients who engaged in physical activity less than five days per week. The study included three clinical visits: at baseline, at six months, and at one year. Assessments included cyclo-ergometry and body composition analysis during the baseline visit and at six-month visit, while 24-hour Holter monitoring was conducted at baseline and at the final visit. Biochemical parameters and microvascular complication risk assessments were performed at every visit.

The ELARA-T1D study aims to investigate the impact of regular, long-standing low-intensity aerobic physical activity on heart rate variability (HRV) and cardiovascular autonomic neuropathy (CAN) in patients with Type 1 Diabetes Mellitus (T1DM). While physical activity is a cornerstone of diabetes management, fear of hypoglycemia and lack of specific guidelines often prevent patients from engaging in exercise. The mechanisms by which physical activity improves cardiovascular outcomes are not yet fully understood. This study focuses on reducing cardiovascular risk in T1DM through an unstructured low-intensity physical activity five days per week for 30-60 min per exercise, in training zone 2. This is a randomized, parallel-assignment longitudinal study. Following a screening phase (0-4 months) to verify inclusion/exclusion criteria and baseline laboratory status, eligible participants had been randomized into two groups: Experimental Group (Group A): Introduction of low-intensity aerobic activity five days per week for 30-60 minutes. The intensity is individually determined via spiroergometry to achieve training zone 2. Control Group (Group B): Maintenance of previous sedentary or low-activity lifestyle (not exceeding 30 minutes, less than five days per week). The physical activity protocol is monitored using heart rate tracking (Garmin watches) to ensure patients stay within the prescribed intensity zones. Assessment of glycemic control using the ambulatory glucose profile (APG) was conducted using a Guardian 4 continuous glucose monitoring (CGM) system (Medtronic, Northridge, CA, USA). The study evaluates the progression of Cardiovascular Autonomic Neuropathy (CAN) using the 24-hour Holter ECG monitoring to assess HRV The assessment schedule is as follows: Baseline (Month 0): Laboratory testing (CBC, UACR, HbA1c, BUN, eGFR, AST, ALT, CK, lipid profile), evaluation of microvascular complications, Cardiac ultrasound, HRV assessment ( 24h Holter), spiroergometry, evaluation of glycemic control using the ambulatory glucose profile (APG). Follow-up (Months 6): Repeat laboratory testing, spiroergometry and APG to track changes in cardiovascular fitness and metabolic control. Final visit (Months 12): Repeat laboratory testing, evaluation of microvascular complications, HRV assessment and APG to track changes in cardiac autonomic function and metabolic control. In addition, all subjects underwent CT coronary angiography. Long-term follow-up: Continuous monitoring every 6 months up to 60 months to evaluate the long-term sustainability of the intervention's effects on cardiovascular health and chronic vascular complications Objectives The primary goal is to determine if consistent, low-intensity exercise can delay the onset of CAN or to prevent progression of incipient CAN and improve cardiovascular fitness.